Mechanical stress effects on electrical breakdown of freestanding GaN thin films. (February 2018)

• Record Type: Journal Article
• Authors: Wang, Tun; Wang, Baoming; Haque, Aman; Snure, Michael; Heller, Eric; Glavin, Nicholas
• Is Part Of: Microelectronics and reliability. Volume 81(2018)
• Page Start: 181
• Page End: 185
• Publication Date: 2018-02
• Subjects: Gallium nitride -- Electrical breakdown -- Mechanical stress; Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2017.12.033
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: Gallium Nitride (GaN) devices are intended to operate at high temperature and mechanical stress conditions, rendering reliability a major concern. To investigate the effects of temperature and stress on electrical breakdown they were applied individually and simultaneously, on free standing epitaxially grown GaN specimens after release from the growth substrate. Both temperature and mechanical stress were seen to degrade the material by decreasing the breakdown voltage. Up to 60% decrease was observed at around 870 MPa. It is hypothesized that stress-generated defects climb to the free surfaces, creating localized leakage current instability or 'ringing' effects. This study also captures the synergy of temperature and stress, which can be translated to breakdown of buffer layers in GaN devices or in designing harsh environment sensors. Highlights: Freestanding GaN films were mechanically stressed, with and without temperature. Both stress and temperature decreased breakdown strength of GaN films. At 870 MPa stress, breakdown strength decreased by up to 60%. Mechanical stress induced defects are hypothesized to create leakage current instabilities.